Telephone system.



No. 859,201. PATENTED JULY 9.1907.

H. P. GLAUSEN.

TELEPHONE SYSTEM.

APPLICATION rmm JULY 1a, 1903.

THE NORRIS PETERS 0 WASHINGTON, u. c.

UNITED STATES PATENT OFFICE.-

HENRY P. CLAUSEN,

OF CHICAGO, ILLINOIS, ASSIGNOR TO AMERICAN ELECTRIC TELEPHONE COMPANY,OF CHICAGO, ILLINOIS, A CORPORATION.

TELEPHONE SYSTEM.

Specification of Letters Patent.

Patented July 9, 1907.

Applieationfiled July 18,1903. Serial NO- 166,184;-

To all whom it may concern:

Be it known that I, HENRY P. CLAUsEN, a citizen of the United States ofAmerica, and a resident of Chicago, Cook county, Illinois, have inventeda certain new and useful Improvement in Telephone Systems, of which thefollowing is a specification.

My invention relates to telephone systems wherein subscribers linesterminate at a central office, at which office means, such as operatorscircuits and devices are provided to variously connect the linestogether for conversational purposes and perform the usual and necessaryoperations attendant upon such connections.

The ordinary and usual arrangement at a central office is to locate theswitch sockets of the subscribers lines upon the switchboard before theoperators and to provide the operators each with a certain number ofpairs of switching plugs, adapted to be inserted in the sockets of thelines, and having insulated contact surfaces to engage correspondingcontact terminals in said sockets. The like contact surfaces of thepairs of plugs are connected by flexible conductive cords so that whenthe plugs of a pair are inserted in the sockets of two lines, the linesare electrically connected together for conversational purposes.Switches are also provided in order to enable the operator to insert hertelephone into the cords, or cord circuits, as they are usually called,to enable her to talk with and receive the message from a callingsubscriber, and to likewise connect the central oflice ringing generatorwith the cord circuits to ring a subscribers bell. It will be apparenttherefore, that to connect two subscribers lines together forinter-communication, the operator is required to insert one plug of apair into the line socket in response to the subscribers call; toconnect her telephone with the cords, to ascertain the number wanted,

and, in accordance with the directions received, to insert the otherplug of the pair into the wanted subscribers switch-socket or jack, asit is sometimes termed, the final act of the series being to connect theringing generator to the plug lastinserted to call the connectedsubscriber. But in such systems where the several connective acts arewholly manual, the opera tors attention must not be diverted from theestablished connection, for the called subscriber may not respond, inwhich case the usual operation is for the operator to connect hergenerator with the cords and ring his-bell again. This throws additionalwork upon the operator besides causing loss of time to the waitingsubscriber and to any others throughout the system who may be wishing toconnect with the lines. It has been proposed to reduce the labor of theoperator by making the disconnection of the calling generator from thecord circuit entirely automatic, so that after she has once inserted theplug into a called-for subscribers jack no further attention on her partis required as the response of the subscriber disconnects the generator.

It is to improvements in this line that my invention specificallyrelates. In carrying out my improvements, I provide means forautomatically cutting off the ringing generator when the calledsubscriber responds, so that conversation may be carried on; and furthermeans whereby the same disconnection takes place and a supervisoryclearing-out signal is exposed, in case the waiting subscriber becomesimpatient, hangs up his telephone and leaves the instrument. There isalso a supervisory signal to indicate the termination of theconversation.

In the drawing which accompanies and illustrates the specification, thefigure is a diagrammatic view indicating two telephone circuits enteringa central oflice together with a switch-cord .circuit arranged to unitethem for the formation of a circuit for a through communication.

L and L represent two telephone circuits extending between theirrespective sub-stations A and A and a central station C. They areprovided at the sub-stations with a telephone receiver 4 and a secondarywinding of an induction coil 5 in a normally open branch or bridgebetween the main conductors l and Z a callbell 3 being arranged in aground branch and the regular telephone switch being adapted whilesupporting the receiving telephone to maintain the normal discontinuityof the telephone bridge or branch as well as the local circuitcontaining the primary winding of the coil 5, and the local battery 6 tosupply current for the transmitter 7. The grounded call-bell 3 isnormally connected by the hook 2 with the main line conductor Z but isopened when the receiver is displaced, the telephone branch and thelocal circuit being closed at this time. At the central station theselines center in a switchboard where they are fitted each withswitchsockets or jacks J, a line signal S, each, moreover, be ing alsoin normal connection with a source of current E, such as a battery.

D represents a switch cord-circuit adapted to form an operative unionbetween the two line circuits. The figure also shows the severalappliances and circuit arrangements employed in carrying out theinvention for the purpose hereinbefore indicated in their normalrelation to one another.

P and P are the switch plugs of ordinary structure, having a tip contactsurface p and a sleeve contact surface 10 which surfaces are adapted toregister respectively, with corresponding line contact surfaces in theplug sockets or jacks J. These surfaces of one of the plugs areelectrically connected with the reverse surfaces of the other, or tip tosleeve and vice versa, by the strands or cords s, s and t, t thesestrands being normally continuous through the resting contacts of theringing key springs 11, a listening key, indicated by the springs 10,being provided to enable the operator to connect her telephone with thecord circuit.

The ringing key comprises as shown diagrammatically a spring operatingmeans, as the plunger 12, adapted when depressed to break the continuityof the cord strands and connect the springs 11, with their'outer contactanvils, the lower of such anvils being joined to the grounded ringinggenerator 13, while the upper is electrically connected with a branchconductor 14 extending to the junction 14, the function of which will behereinafter described. An armature is carried by the ringing key 12which when depressed is within the magnetic field of a magnet m whosecircuit is closed through the resistance 20 by the armature 17 strikingagainst the grounded contact spring 18, the other terminal of thewinding of the magnet being connected by the conductor 21 to thejunction 22. A short circuiting branch 23 for the magnet m extends fromthe point 24 to the front contact anvil of the relay r being completedby the armature of said relay to the juncture 25.

A supervisory relay r having double coils either of which is alonecapable of attracting the armature, is bridged by the conductors 26 and27 across the cord cir cuit, its coils having sufficient impedance tovoice currents to prevent their passage thereacross. The middle point ofthese coils is connected by a conductor 16, to the battery lead 9.emerging from the battery E and connecting normally with the subscriberslines for the operation of their signals. This conductor contains thewindings of the relay 1' before mentioned, and from the point 25 aconductor 28 leads to the armature of the supervisory relay rwhichgoverns through its forward contact anvil, the circuit of lamp 15.

The ringing and listening keys may be of any mechanical structure whichwill successfully perform the desired operations.

In operation, the subscriber A, for example, indicates a call at thecentral station by taking up his re ceiver, which act closes the mainconductors together,

. and forms a path from the battery E over the conductor 9, the metallicline circuit to the sub-station and back to the central stationandthrough the signal S. It will be noticed that the line conductor 1 withwhich the battery E is connected stands normally open at the subscribersstation so that there is no undue waste of current. The operatorobserving the signal inserts the answering plug P into the jacket orsocket J, thus cutting off the battery E and the signal S which is alsorestored, and she then connects her head telephone with the cord circuitby means of the key'springs 10. Upon learning the number of the partywanted, the calling plug P is inserted in the jack of that subscriber,and the calling key plunger 12 depressed. The depression of said plungerconnects the lower spring 11 with the generator 13 which sends ringingcurrent out to the sub-station through the cord-strand t the line WireP, the switch hook and through the call hell 3 to ground, thus ringingthe subscribers bell. The other spring 11 of the ringing key is now incontact with the terminal of Wire 14. The armature 17 on the key plungerin its movement closed spring 18 upon its contact to cause theexcitation of magnet m from the battery E over a circuit there- -throughcommunication.

from, including lead 9, conductor 16 to the junction 25, conductor 28 tothe point 22, branch 21, winding of magnet m, resistance 20 and spring18 to ground. This holds the armature and key in depressed positionuntil the magnet m is deenergized in either of the following ways.tallic path for the ringing current is provided back to the centraloffice over the line conductor lithe tip of the plug, strand 8 branch 14to point 14, conductor 16 through relay 2 to point 25; from here thecurrent has two paths, one through 16 and 9 to the battery and earth,and the other through conductors 28 and 22, mag net wt, resistance 20and spring 18 to ground. The cur rent now flowing through the relay T issufiicient to operate it, it being responsive to the alternating ringingcurrent, and its armature closes the short circuit 23 about magnet m,the resistance 20 serving to prevent short circuiting the battery E,which magnet loses its magnetism and allows the plunger under theinfluence of its spring to return to normal position, thus breakingconnection at the spring 18 and from the generator 13 and branch 14, andcompleting the cord circuit for connecting the generator is when thewaiting or calling subscriber hangs up his receiver. This completes acircuit for relay 1 from the battery E, conductors 9 and 16, relay H.the lower coil of relay 1' conductor 26, strand S of the cord circuit,main line conductor Z to ground through the signaling bell. This alsocauses the excitation of the relay r to close the short circuit aboutmagnet m to disconnect the generator 13, and at the same time itoperates relay r to light the supervisory lamp 15 from the battery Eover conductors 9, 16, and 28. The operator seeing this signal may takedown the connection. At the termination of the conversation, thereplacement of the receiver at one sub-station will complete a circuitthrough one coil of relay r as just traced, and a like act at the otherstation will close a corresponding circuit through the other coil, bothcoils of the relay thus being brought into operation for safety andconvenience by the tip and sleeve connection of the cord strands asbefore described. The operator observing the lighting of lamp 15 willwithdraw the plugs and take down the connection.

It is sometimes convenient to dispense with the auxiliary groundconnections at the centralstation and in lieu thereof to provide returnconductors or a commonreturn to the complementary battery pole. This, ofcourse, is an immaterial change and may or may not be made, aspreferred, by those practicing the invention.

As a matter of course, switchboard apparatus containing my inventionwill comprise as many switch-cord circuits as are necessary for theproper conduct of the business of switching lines together or toaccommodate the traffic. Good results have been obtained with re- First:If the'called subscriber responds, a me The second manner of dis laycoils r of 5000 ohms resistance, relay 1 of 5000 ohms in connecting thegenerator with the cord circuit to thereby hold the key in operatedposition, a relay connected with the cord circuit and controlling thecontinuity of a short circuit about the magnet, said relay beingoperated by the response of the called subscriber to restore the key andall related parts to normal position.

2. In a telephone system, subscribers lines, a cord circuit connectingsaid lines for conversation, a ringing key and a ringinggenerator tocall the wanted subscriber, a magnet whose circuit is closed by theoperation of the key in connecting the generator with the cord circuitto thereby hold the key in operated position, a relay con nected withthe cord circuit and controlling the continuity of a short circuit aboutthe magnet, said relay being operated by the response of the calledsubscriber or by the replacement of the calling subscribers receiver.

3. In a telephone system, subscribers lines having grounded call bellsat the substations, a cord circuit, a ringing generator, means tomaintain said generator in connection with the cord circuit to signalthe called subscriber, until the latter answers, a relay also connectedwith the cord circuit to control such means, said relay being operatedby the ringing current when the called subscriber responds to disconnectsaid generator from the cord circuit together with a supervisorysignaling device circuit together with a supervisory signaling deviceadapted to be brought into operation simultaneously with the operationof the means by which the calling subscriber automatically disconnectsthe source of ringing current from the called subscribers line.

-l. In a telephone system, subscribers metallic lines, having groundedsignaling bells, a cord circuit connecting two lines together, agrounded ringing generator connected with said cord circuit to ring thecalled subscribers bell over one line conductor and ground, a relayconnected between the other line conductor and ground at the centraloli'lce. a magnet to hold the generator in connection with the cordcircuit. and a short circuit about the magnet controlled by the relay.

5. In a telephone system, subscribers metallic lines, having groundedsignaling bells, a cord circuit connecting two lines together, agrounded ringing generator connected with said cord circuit to ring thecalled subscribers bell over one line conductor and ground, a relayconnected with the corresponding line conductor of the callingsubscriber, a battery and ground at the central office, a magnet to holdthe ringing generator in connection with the cord circuit, a shortcircuit of said magnet controlled by said relay, whereby when thecalling subscriber hangs up his receiver the said relay is operated bybattery current over one of the calling subscribers line conductors andground, to short circuit the magnet and disconnect the generator.

(3. I11 a telephone system, subscribers metallic lines, having groundedsignaling bells, a cord circuit connecting two lines together, agrounded ringing generator connected with said cord circuit to ring thecalled subscribers bell over one line conductor and ground, a groundedbranch from the cord strand, two relays and a battery in said branch, amagnet to hold the generator in operative con nection with the cordcircuit, a short circuit of said magnot controlled by one of said relaysand a supervisory sig nal controlled by the other, whereby when thecalling subscriber replaces his instrument the relays are operated overthe grounded line conductor to short circuit the magnet to disconnectthe generator and expose the supervisory signal together with asupervisory signaling device adapt ed to be brought into operationsimultaneously with the operation of the means by which the callingsubscriber automatically disconnects the source of ringing current fromthe called subscriber's line.

T. In a telephone system, subscribers metallic line circuits havingcall-bells grounded from one line conductor, a cord circuitconnecting'two lines for conversation and having its strands extendingfrom the tip of one plug to the sleeve of the other, a ringing keyadapted to sever the cord strands, a grounded ringing generatorconnected-with one strand of the calling plug to ring the calledsubscribers bell, a magnet to hold the generator so connected, a relayto control said magnet, said relay being connected with the other strandof the cord circuit to both plugs and with a grounded battery, wherebywhen the called subscriber responds the said relay is operated byringing current over his metallic line or when the calling subscriberreplaces his receiver the relay is operated by battery current over oneof his line conductors and ground, in either case to disconnect thegenerator.

8. In a telephone system, subscribers metallic lines, having groundedbells, a cord circuit having its strands connected from the tip of oneplug to the sleeve of the other, a ringing key, a grounded ringinggenerator, a magnet operated over a local circuit closed by the soundkey to signal the called subscriber, a bridge of the cord circuit, adouble coil relay in said bridge, a conductor extending from between thecoils of the relay to the ground. :1 common battery and another relay insaid conductor, a short circuit for said magnet controlled by the latterrelay, another branch conductor from between the two relays closed bythe ringing key to the line of the called sub scribcr, and a supervisorylamp controlled by said bridged relay.

9. In a telephone system, the combination of subscribers lines,subscribers hook switches, jacks connected with the lines, operatorscord circuits having plugs adapted for insertion in said jacks, bellsassociated with the said hook switches, a source or current associatedwith the said cord circuit and arranged to be connected with either linefor the purpose of ringing either of said bells, an electric lockingdevice for temporarily maintaining the connection between said source ofcurrent and the cord circuit, a normally open shunt around said electriclocking device, a relay for opening and closing said shunt, and suitableconnections whereby said relay may be controlled by either of said hookswitches together with a supervisory signaling device adapted to bebrought into operation simultaneously with the operation of the means bywhich the calling subscriber automatically disconnects the source ofringing current from the called subscriber's line.

10. In a telephone system, the combination of sub scribers' bells, asource of current at the central station for ringing said bells, anelectric locking device for maintaining the flow of current from saidsource until the called subscriber answers, or until the callingsubscriber hangs up his receiver, a normally open shunt around saidlocking device, a supervisory relay, an auxiliary relay for opening andclosing said shunt, a battery, and circuit connections whereby thecircuit of said auxiliary relay includes said battery and saidsupervisory relay.

11. In a telephone system, the combination of a subscribers line, asubscribers bell, a source of current at the central station for ringingsaid bell, an electric locking device for causing a constant projectionof ringing current onto the line, a supervisory electro-magnet connectedand arranged to be energized when the subscriber answers the call, andelectrically operated means in the circuit of said supervisory relayadapted and arranged to release said locking device when the subscriberanswers the call to gether with a supervisory signaling device adaptedto be brought into operation simultaneously with the operation of themeans by which the calling subscriber automatically disconnects thesource ofringing current from the called subscriber's line.

Signed by me at Chicago, Cook county, Illinois, this 15th day of July,1903.

HENRY I. CLAUSEN.

Witnesses A. F. DURAXD, WM. A. I-Innnnns.

